Commit a7681525 authored by Nick Mathewson's avatar Nick Mathewson 🤹
Browse files

Add function to clear publish bindings. 

When we clean up, we'd like to clear all the bindings that refer to
a dispatch_t, so that they don't have dangling pointers to it.
parent 271a6718

src/lib/pubsub/pubsub_build.c

+25 −5
Original line number Diff line number Diff line
@@ -242,10 +242,10 @@ pubsub_connector_define_type_(pubsub_connector_t *con, 
 * for <b>d</b>.

 */

static void

dispatch_fill_pub_binding_backptrs(pubsub_builder_t *builder,

pubsub_items_install_bindings(pubsub_items_t *items,

                              dispatch_t *d)

{

  SMARTLIST_FOREACH_BEGIN(builder->items->items, pubsub_cfg_t *, cfg) {

  SMARTLIST_FOREACH_BEGIN(items->items, pubsub_cfg_t *, cfg) {

    if (cfg->pub_binding) {

      // XXXX we could skip this for STUB publishers, and for any publishers

      // XXXX where all subscribers are STUB.
@@ -254,13 +254,29 @@ dispatch_fill_pub_binding_backptrs(pubsub_builder_t *builder, 
  } SMARTLIST_FOREACH_END(cfg);

}



/**

 * Remove the dispatch_ptr fields for all the relevant publish bindings

 * in <b>items</b>.  The prevents subsequent dispatch_pub_() calls from

 * sending messages to a dispatcher that has been freed.

 **/

void

pubsub_items_clear_bindings(pubsub_items_t *items)

{

  SMARTLIST_FOREACH_BEGIN(items->items, pubsub_cfg_t *, cfg) {

    if (cfg->pub_binding) {

      cfg->pub_binding->dispatch_ptr = NULL;

    }

  } SMARTLIST_FOREACH_END(cfg);

}



/**

 * Create a new dispatcher as configured in a pubsub_builder_t.

 *

 * Consumes and frees its input.

 **/

dispatch_t *

pubsub_builder_finalize(pubsub_builder_t *builder)

pubsub_builder_finalize(pubsub_builder_t *builder,

                        pubsub_items_t **items_out)

{

  dispatch_t *dispatcher = NULL;

  tor_assert_nonfatal(builder->n_connectors == 0);
@@ -276,7 +292,11 @@ pubsub_builder_finalize(pubsub_builder_t *builder) 
  if (!dispatcher)

    goto err;



  dispatch_fill_pub_binding_backptrs(builder, dispatcher);

  pubsub_items_install_bindings(builder->items, dispatcher);

  if (items_out) {

    *items_out = builder->items;

    builder->items = NULL; /* Prevent free */

  }



 err:

  pubsub_builder_free(builder);

src/lib/pubsub/pubsub_build.h

+15 −5
Original line number Diff line number Diff line
@@ -32,6 +32,13 @@ typedef struct pubsub_builder_t pubsub_builder_t; 
 **/

typedef struct pubsub_connector_t pubsub_connector_t;



/**

 * A "pubsub items" holds the configuration items used to configure a

 * pubsub_builder.  After the builder is finalized, this field is extracted,

 * and used later to tear down pointers that enable publishing.

 **/

typedef struct pubsub_items_t pubsub_items_t;



/**

 * Create a new pubsub_builder. This should only happen in the

 * main-init code.
@@ -75,13 +82,16 @@ void pubsub_connector_free_(pubsub_connector_t *); 
 * This should happen after every subsystem has initialized, and before

 * entering the mainloop.

 */

struct dispatch_t *pubsub_builder_finalize(pubsub_builder_t *);

struct dispatch_t *pubsub_builder_finalize(pubsub_builder_t *,

                                           pubsub_items_t **items_out);



/**

 * Clear all pub_binding_t backpointers in <b>items</b>.

 **/

void pubsub_items_clear_bindings(pubsub_items_t *items);



#ifdef PUBSUB_PRIVATE

struct pubsub_items_t;

#define pubsub_items_free(cfg) \

  FREE_AND_NULL(pubsub_items_t, pubsub_items_free_, (cfg))

void pubsub_items_free_(struct pubsub_items_t *cfg);

#endif

void pubsub_items_free_(pubsub_items_t *cfg);



#endif

src/lib/pubsub/pubsub_builder_st.h

+3 −3
Original line number Diff line number Diff line
@@ -91,12 +91,12 @@ typedef struct pubsub_type_cfg_t { 
 * The set of configuration requests for a dispatcher, as made by various

 * subsystems.

 **/

typedef struct pubsub_items_t {

struct pubsub_items_t {

  /** List of pubsub_cfg_t. */

  struct smartlist_t *items;

  /** List of pubsub_type_cfg_t. */

  struct smartlist_t *type_items;

} pubsub_items_t;

};



/**

 * Type used to construct a dispatcher.  We use this type to build up the
@@ -111,7 +111,7 @@ struct pubsub_builder_t { 
  int n_errors;

  /** In-progress configuration that we're constructing, as a list of the

   * requests that have been made. */

  pubsub_items_t *items;

  struct pubsub_items_t *items;

  /** In-progress configuration that we're constructing, in a form that can

   * be converted to a dispatch_t. */

  struct dispatch_cfg_t *cfg;

src/test/test_pubsub_msg.c

+1 −1
Original line number Diff line number Diff line
@@ -148,7 +148,7 @@ setup_dispatcher(const struct testcase_t *testcase) 
    tor_free(sys);

  }



  return pubsub_builder_finalize(builder);

  return pubsub_builder_finalize(builder, NULL);

}



static int